Food packaging bag materials can be classified into the following main categories:

Plastic Materials

• Polyethylene (PE)
  • Low-density polyethylene (LDPE): It has good flexibility, transparency, and heat sealability. It is often used for packaging fresh fruits and vegetables, bread, and some light-duty items.
  • High-density polyethylene (HDPE): It is more rigid and has better mechanical strength and barrier properties against water vapor. It is suitable for packaging milk, juices, and some solid foods like grains.
• Polypropylene (PP): It has high heat resistance, can be sterilized at high temperatures, and has good transparency and gloss. It is widely used in packaging for instant noodles, biscuits, and some frozen foods.
• Polyvinyl Chloride (PVC): It has excellent transparency and mechanical properties. However, due to potential safety concerns related to the release of harmful substances, its use in food packaging is being restricted in some cases. It was formerly used for packaging meat products and some fresh foods.
• Polystyrene (PS): It has good rigidity and insulation properties. It is often used to make disposable food containers, such as those for fast food and takeout.

Paper Materials

• Kraft Paper: It has high strength and good water resistance. It is commonly used for packaging bulk foods like flour, sugar, and coffee beans. It can also be made into paper bags for packaging snacks and some baked goods.
• Coated Paper: By coating the surface of the paper with materials like polyethylene or wax, its moisture resistance and barrier properties are enhanced. It is often used for packaging ice cream, milk cartons, and some snack packaging.
• Paperboard: It is thicker and more rigid than ordinary paper, providing better protection for products. It is widely used in the packaging of canned foods, chocolates, and some high-end food gift boxes.

Metal Materials

• Tinplate: It has good corrosion resistance and barrier properties. It is mainly used for making cans to package canned fruits, canned meat, and beverages.
• Aluminum Foil: It has excellent barrier properties against light, oxygen, and water vapor, and is also malleable. It is often used for packaging chocolates, pharmaceutical tablets, and some high-end food products that require high protection. It can also be used as a heat-resistant material in some food packaging.

Composite Materials

• Paper-Plastic Composites: They combine the advantages of paper and plastic, such as good printing performance of paper and moisture resistance of plastic. They are used in packaging for snacks, instant noodles, and some dry food products.
• Aluminum-Plastic Composites: They have excellent barrier properties and are often used for packaging products that require high preservation, such as milk powder, coffee powder, and some medical foods.
• Multilayer Composites: These usually consist of multiple layers of different materials, such as a combination of plastic, paper, and aluminum foil, to achieve comprehensive performance optimization. They are used in high-end food packaging and some special food packaging that requires long-term preservation.

Other Materials

• Glassine Paper: It is a translucent paper with good grease resistance and moisture resistance, often used for packaging bakery products, candies, and some light snacks.
• Cellophane: It is a transparent, biodegradable material with good moisture resistance and oxygen permeability. It is used for packaging some confectionery and bakery products.